<TITLE>WAISandGopher -- /FAQ</TITLE>
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<H1>W3 vs WAIS and Gopher</H1>
<H2>Question</H2>What's the difference betwen W3 and WAIS? What's the difference between
W3 and Gopher? Why invent yet another system? Which one should I use?
<H2>The data model</H2>W3 is comparable to both <A NAME=3 HREF=../../Products/WAIS/Overview.html>WAIS</A> and <A NAME=4 HREF=../../Products/Gopher/Overview.html>Gopher</A> , in that it is a client-server
information system running over the internet.  There is a difference
in the data models.  The W3 model is that everything (document, menu,
index etc) is represented to the user as a hypertext (hypermedia)
object.  There two <A NAME=8 HREF=../Terms.html#navigation>navigation</A> operations are available to the user:
to follow a link or to send a query to a server.  Only certain documents
are flagged as having a search facility, and not all documents have
links, but some documents have both.  That's a pretty simple model,
and results in a pretty simple user interface.<P>
Two neat things fall out of this model.  One is that it turns out
that almost all other information systems can be represented in terms
of W3 documents.  A W3 user can interrogate WAIS indexes (<A NAME=5 HREF=http://info.cern.ch:8001/microworld.media.mit.edu:8000/POETRY?>example</A>)
and Gopher servers (<A NAME=6 HREF=../../DataSources/bySubject/Overview.html#weather>example</A>).  This comes from the flexibility of
the W3 model to describe other structures.  A WAIS database is a searchable
document. The hit-list returned by a WAIS server (or any other query
engine) is a hypertext document with links to the documents found.
Gopher menus (or any other hierarchical menu system, including a file
system) are represented as lists of items linked to other objects.
The W3 system has an open <A NAME=2 HREF=../Addressing/Addressing.html>addressing scheme</A> allowing links to be made
to any objects on W3, WAIS, Gopher, FTP, NFS, or Network News servers.<P>
This flexibility has allowed lots of different kinds of data to be
put on-line by writing a <A NAME=1 HREF=../Provider/Overview.html#14>simple script</A> to generate a hypertext "view"
of the database. <P>
The hypertext model, then, is flexible. It is also powerful as a communications
medium.  To author a document in hypertext is to communicate better.
It allows one to put in a <A NAME=7 HREF=../Terms.html#link>link</A> whenever  the reader might need <A NAME=9 HREF=../WhatIs.html>background
information</A> .  
<H2>WAIS without links</H2>You miss the links in WAIS in two ways. One is when you are looking
for an index. You can't follow links from an overview page to "browse"
through different indexes. You can only use a master index (the directory
of sources) to find indexes.  The other way is that when you have
retrieved something, whether part of the FORTRAN manual or part of
a mail discussion, you get it in isolation. You can't follow links
from that document to related documents.
<H2>Gopher without text</H2>A Gopher menu is a dry list of items.  Each line has 80 characters
in which to describe an option. In practice, to communicate with the
reader, one needs the full power of text formatting in a number of
styles. A plain list  turns out to be relatively infrequently used
when the author or the program generating the document has a choice.
 Note that the "Panda" project adds some plain text to Gopher menus,
but this is only a small step toward the flexible blending of links
and text which is hypertext.
<H2>Group work</H2>The second big difference is that W3 is designed to include collaborative
authoring  (CSCW) so that groups can share information, rather than
simply individuals disseminate it.  We only have a first stab at this
on the NeXT platform, as we were overtaken by the web's success in
dissemination mode. 
<H2>Deployment levels</H2>The W3 software is not (May 92) as deeply deployed  as WAIS and Gopher
software. This is basically because it takes more time to write a
hypertext client than a menu or query client.  (Also, because the
initial W3 instigators are paid to work for the world of High-Energy
Physics primarily).<P>
However, the W3 world is growing very fast.  There is widespread recognition
that hypertext is essential for the next generation. It is planned
to merge the W3 and Gopher systems, and there is no reason (apart
from server simplicity and, perhaps, response time) why both of these
systems could not use the WAIS protocol when it settles down.
<H2>The Choice</H2>Bear in mind:
<UL>
<LI>A W3 client can read data from any other system.
<LI>If you run a W3 server you can upgrade certain parts of the documentation
to hypertext later.
<LI>Hypertext is neat for representing existing data easily.
</UL>So install W3 clients, and W3 servers. If you want to install a Gopher
or WAIS server, fine: the W3 clients will access it.  If you install
a WAIS server, then you could install the W3-WAIS gateway locally
to save bandwidth.<P>
_________________________________________________________________
<ADDRESS><A NAME=0 HREF=http://info.cern.ch./hypertext/TBL_Disclaimer.html>Tim BL</A>